1. Field of the Invention.
The present invention relates generally to locking a nut and bolt fastener assembly and, more particularly, to a system for locking a pinch bolt assembly through the yoke of a motor vehicle steering assembly.
2. Description of the Prior Art.
Various rotatable adjusting bushings have been used to adjust castor and camber in wheeled vehicle steering mechanisms. Such steering mechanisms typically include a yoke carried at an end of a front axle. At least one arm of the yoke has an opening for receiving the adjusting bushing. A wheel spindle assembly is pivotally mounted on the yoke by ball joints having a stud extending through the opening in the yoke arm, in locking engagement with the bushing. The adjusting bushing displaces the associated ball joint from the axis of the exterior surface of the bushing. The orientation of the bushing within the opening determines the direction of the displacement, which is reflected as a change in the pivotal axis of the spindle and thus as changes in castor, camber or both.
Copending U.S. Patent Application Serial No. 104,323, filed Oct. 2, 1987, describes such a steering mechanism in connection with an adjustable bearing positioning system. Adjustable bearings have a cylindrical outer surface approximately equal in circumference with the bushing receiving opening. A shoulder extends from the top of the bushing and a slot extends vertically through the bushing and shoulder and radially outward from a vertical bore in the bushing. The shape of the bore mates with the stud in the opening. The bore is parallel to but offset from the central axis of the outer cylindrical surface. A further slot extends radially outward from the bushing receiving opening through the yoke arm. A bolt extending through the yoke arm and through the yoke arm slot cooperates with a nut for pinching the slot and thereby reducing the diameter of the bushing receiving opening for fixing the position of a bushing disposed in the opening.
Motor vehicles, among much other machinery, generate a great deal of vibration in use. Vibration tends to result in nuts coming loose from bolts. As the pinch bolt and nut assembly loosens, the taut grip of the bushing receiving opening on the bushing can loosen, resulting in potential loss of bushing adjustment and loss of castor and camber adjustment.